The said smart cards generally include a card body which holds an electronic module comprising the traditional control unit (e.g. a central processing unit or CPU) and at least one memory. In the various above-mentioned fields, techniques evolve more and more quickly, especially smart card techniques.
For example, in the field of mobile telephony, there are second generation cards and portable telephones as well as third generation cards and portable telephones. The first cards and telephones are designed for use on a GSM (Global System for Mobile communications) network. The said cards are compatible with the standard GSM TS 11.11, a standard published by a standardization institute called the ETSI. The second cards and telephones are designed for use on a GSM network but also on other networks such as UMTS (Universal Mobile Telecommunications System) or GPRS (General Packet Radio Service), standards published respectively by a standardization institute called 3GPP and by the ETSI. The said cards are therefore compatible with the standard GSM TS 11.11 as well as with the standard USTM TS 31.102 (card standard adapted for the UMTS network), standards published by the ETSI and 3GPP standardization institutes. In the third generation standard, the card includes memories concerning applications independent from each other. For example, we have a SIM application operating on a GSM network and a USIM application operating on a UMTS network, a banking application and an application operating on a GSM network, etc. Each of these applications has its own environment to operate autonomously. So, for example, each application has its own identification means such as keys, its own means of counting the units used during a telephone call, etc. The files in the tree structures of the various memories comprise the said means.
However, for simplicity of use, if a user has a card with a subscription that operates in a third generation portable telephone, he must also be able to use his card with the same subscription on a second generation portable telephone.
Consequently, the various applications use certain identical items of data, e.g. the telephone numbers, the units used during a telephone call, etc. Current techniques propose devices which store an image of the data in a first memory in a second memory, i.e. a copy of the tree structure files stored in the first memory is also stored in the second memory so that two different applications can use the same data.
The solution proposed by current techniques has the disadvantage of using a considerable amount of memory in the smart card, which may represent a problem due to the limited memory size in smart cards. Also, in order to ensure that the data and its image is coherent, means must be implemented to update the data as well as its image in the two memories. These means present the disadvantages of requiring considerable execution time and being difficult to manage since data must not be lost between consecutive updates of the two memories.
A technical problem to be solved by this invention is to propose an integrated circuit device including one memory which has first and second memories, the two memories comprising files organized in respective tree structures, which would reduce the amount of space taken up in the memory by the data and also reduce the time to update the data comprised in the files without losing the said data.